CODEWITHSUNDEEP
iosopencvlinkerxamarin.iosios-simulator
Alex Gray
Alex Gray

Reputation: 61

Linking OpenCV with MonoTouch returns "Undefined symbols for architecture i386" error

I am getting this error which I try to add my OpenCV based library to a MonoTouch project:

Undefined symbols for architecture i386:
      "cv::isContourConvex(cv::_InputArray const&)", referenced from:
  aruco::MarkerDetector::detectRectangles(cv::Mat const&, std::vector<aruco::MarkerDetector::MarkerCandidate, std::allocator<aruco::MarkerDetector::MarkerCandidate> >&)in libAruco.a(markerdetector.o)
      "cv::warpPerspective(cv::_InputArray const&, cv::_OutputArray const&, cv::_InputArray const&, cv::Size_<int>, int, int, cv::Scalar_<double> const&)", referenced from:
  aruco::MarkerDetector::warp_cylinder(cv::Mat&, cv::Mat&, cv::Size_<int>, aruco::MarkerDetector::MarkerCandidate&)in libAruco.a(markerdetector.o)
  aruco::MarkerDetector::warp(cv::Mat&, cv::Mat&, cv::Size_<int>, std::vector<cv::Point_<float>, std::allocator<cv::Point_<float> > >)in libAruco.a(markerdetector.o)
      "cv::FileNodeIterator::readRaw(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned char*, unsigned long)", referenced from:
  cv::VecReaderProxy<float, 1>::operator()(std::vector<float, std::allocator<float> >&, unsigned long) constin libAruco.a(board.o)
      "cv::FileNodeIterator::FileNodeIterator(CvFileStorage const*, CvFileNode const*, unsigned long)", referenced from:
  cv::FileNode::begin() constin libAruco.a(board.o)
  cv::FileNode::end() constin libAruco.a(board.o)

This is only a sample of the full list of opencv methods which are having this problem, as it is easily over 100.

I'm attempting to run this in the simulator (I only have the trial edition of monotouch). I'm compiling for the ipad simulator in xcode and have followed the Opencv tutorial as far as setting up my project with the pre-built framework from their website. I was maybe wondering if there is some linker flag I need to enter as my static library is not as large as I would expect it to be given the fact it needs to link with several of the opencv modules (that's just a gut feeling and not necessarily indicative of anything).

I suppose its also important to mention that I have very little experience with iOS and MonoTouch development, so I could have missed something really simple.

Upvotes: 1

Views: 778

Answers (1)

poupou
poupou

Reputation: 43553

Your static library might not be a FAT (multiple architectures) library or may not include i386 code.

The easy way to find out is to try, from a terminal window:

lipo -info libAruco.a

That should return something like:

Architectures in the fat file: libAruco.a are: i386 ...

where ... is likely armv7 (or more) to support the iOS devices.

OTOH if i386 is missing then it means your library is not compiled to work on the simulator. In such case you'll need to return to Xcode to build this architecture and use lipo to create a FAT library (that includes both the arm and i386 architectures).

Upvotes: 2

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